Tribulus Terrestris

 

Tribulus Terrestris Clinical Report Summary

Written Exclusively for MyNutritionStore.com by Sarah Dzida 

 

Tribulus terrestris is a natural product used to increase sexual potency in males, treat coronary artery disease and enhance exercise performance; researchers are also considering tribulus's effect on infertility in females, but results, while encouraging, require further research (1).  In the case of men, evidence suggests that tribulus, as a non-steroidal alternative, increases sperm count, sperm viability and increases a man's sexual libido (2).  A non-randomized, controlled study also supported evidence that a statistically greater coronary heart disease remission rate was achieved by patients who were treated with tribulus (3).  In contrast, researchers remain ambiguous as to tribulus terrestris's effect on exercise performance due to limited data (4). 

 

Tribulus Terrestris Overview

 

Tribulus terrestris is a plant with spiny fruit found in tropical and sub-tropical climates; it contains two major alkaloid fractions made up of beta-carboline indoleamines: harmane and norharmane, as well as saponin protodioscins and their respective sulfates (7,8).  Used for a variety of conditions throughout history, tribulus has been utilized in physical rejuvenation tonics; therapies for conditions affecting the liver, kidney, cardiovascular and immune systems; and for increasing muscle strength and sexual potency.  While many studies encourage the effectiveness of tribulus, researchers agree that larger studies, randomized controlled trials and more information are needed to make firmer conclusions (1-6).  However, tribulus's position as a common natural remedy in Chinese and Auyervedic medicine as well as continued speculation by modern medical researchers suggest tribulus and its benefits have yet to be completely drawn out.

 

Safe Use of Tribulus Terrestris

 

As of yet, there is no dosage standardization for tribulus, but experts say it is safe if taken orally in appropriate doses by healthy people.  People allergic or hypersensitive to tribulus terrestris, its constituents, or the calthrop plant family, should not take tribulus.  Patients with menstrual disorders, benign prostatic hyperplasia, prostate cancer, diabetes, or people who use steroid or hypoglycemic medication, beta-blockers, calcium channel blockers, or digoxin should exercise caution also (5,6). 

 

Clinical Studies for Tribulus Terrestris

 

1. Tribulus Terrestris and Increased Sexual Libido

 

Aphrodisiac properties of Tribulus Terrestris extract (Protodioscin) in normal and castrated rats. Gauthaman K, Adaikan PG, Prasad RN. (9)

Tribulus terrestris (TT) has long been used in the traditional Chinese and Indian systems of medicine for the treatment of various ailments and is popularly claimed to improve sexual functions in man. Sexual behaviour and intracavernous pressure (ICP) were studied in both normal and castrated rats to further understand the role of TT containing protodioscin (PTN) as an aphrodisiac. Adult Sprague-Dawley rats were divided into five groups of 8 each that included distilled water treated (normal and castrated), testosterone treated (normal and castrated, 10 mg/kg body weight, subcutaneously, bi-weekly) and TT treated (castrated, 5 mg/kg body weight, orally once daily). Decreases in body weight, prostate weight and ICP were observed among the castrated groups of rats compared to the intact group. There was an overall reduction in the sexual behaviour parameters in the castrated groups of rats as reflected by decrease in mount and intromission frequencies (MF and IF) and increase in mount, intromission, ejaculation latencies (ML, IL, EL) as well as post-ejaculatory interval (PEI). Compared to the castrated control, treatment of castrated rats (with either testosterone or TT extract) showed increase in prostate weight and ICP that were statistically significant. There was also a mild to moderate improvement of the sexual behaviour parameters as evidenced by increase in MF and IF; decrease in ML, IL and PEI. These results were statistically significant. It is concluded that TT extract appears to possess aphrodisiac activity probably due to androgen increasing property of TT (observed in our earlier study on primates).

 

Sexual effects of puncturevine (Tribulus terrestris) extract (protodioscin): an evaluation using a rat model. Gauthaman K, Ganesan AP, Prasad RN. (10)

OBJECTIVE: Apart from its claims for improvement of sexual functions in men, the puncturevine plant (Tribulus terrestris: TT) has long been considered as an energizer and vitalizer in the indigenous system of medicine. Sexual behavior and intracavernous pressure (ICP) measurements were taken in rats to scientifically validate the claim of TT [containing protodioscin (PTN)] as an aphrodisiac. MATERIALS AND METHODS: Forty sexually mature male Sprague-Dawley rats were randomly divided into four groups of 10 each. Group I served as a control group and groups II, III, and IV were treated with three different doses of TT extract (2.5, 5 and 10 mg/kg body weight, respectively), orally, once daily for 8 weeks. Weight was recorded and the rats from all four groups were subjected to sexual behavior studies with primed females and various parameters namely mount and intromission frequencies (MF and IF, respectively), mount, intromission and ejaculation latencies (ML, IL, and EL, respectively) as well as postejaculatory interval (PEI) were recorded. In addition, blood pressure and ICP were recorded for all rats at the end of study. RESULTS: Increases in body weight (by 9, 23, and 18% for groups II, III & IV) and ICP (by 43% and 26% for groups III and IV) were statistically significant compared to the control group. Increases in MF (by 27% and 24%) and IF (by 19% and 22%) for the groups III and IV were statistically significant. Decreases in ML (by 16%, 23%, and 22% for groups II, III, and IV) and PEI (by 20% for group III) were statistically significant compared to the control. CONCLUSIONS: The weight gain and improvement in sexual behavior parameters observed in rats could be secondary to the androgen increasing property of TT (PTN) that was observed in our earlier study on primates. The increase in ICP which confirms the proerectile aphrodisiac property of TT could possibly be the result of an increase in androgen and subsequent release of nitric oxide from the nerve endings innervating the corpus cavernosum.

  

2. Tribulus Terrestris and Enhanced Exercise Performance

 

The effects of Tribulus terrestris on body composition and exercise performance in resistance-trained males. Antonio, J., Uelmen, J., Rodriguez, R., and Earnest, C.

The purpose of this study was to determine the effects of the herbal preparation Tribulus terrestris (tribulus) on body composition and exercise performance in resistance-trained males. Fifteen subjects were randomly assigned to a placebo or tribulus (3.21 mg per kg body weight daily) group. Body weight, body composition, maximal strength, dietary intake, and mood states were determined before and after an 8-week exercise (periodized resistance training) and supplementation period. There were no changes in body weight, percentage fat, total body water, dietary intake, or mood states in either group. Muscle endurance (determined by the maximal number of repetitions at 100-200% of body weight) increased for the bench and leg press exercises in the placebo group (p <.05; bench press +/-28.4%, leg press +/-28.6%), while the tribulus group experienced an increase in leg press strength only (bench press +/-3.1%, not significant; leg press +/-28.6%, p <.05). Supplementation with tribulus does not enhance body composition or exercise performance in resistance-trained males.

 

Tribulus Terrestris References

 

1. Tabakova, P., Dimitrov, M., Ognyanov, K., and et al. Clinical study of Tribestan in females with endocrine sterility. Documentation for Registration (unpublished) 1999.
2. Protich, M., Tsvetkoy, D., Nalbanski, B., Stanisalvov R., and Katsarova, M. [Clinical trial of a tribestan preparation in infertile men]. Akush.Ginekol.(Sofiia) 1983;22(4):326-329.
3. Wang, B., Ma, L., and Liu, T. [406 cases of angina pectoris in coronary heart disease treated with saponin of Tribulus terrestris]. Zhong Xi Yi Jie He Za Zhi or (Chung Hsi I Chieh Ho Tsa Chih) or (Chinese Journal of Modern Developments in Traditional Medicine) 1990;10(2):68, 85-87.
4. Antonio, J., Uelmen, J., Rodriguez, R., and Earnest, C. The effects of Tribulus terrestris on body composition and exercise performance in resistance-trained males. Int J Sport Nutr Exerc.Metab 2000;10(2):208-215.
5. Li, M., Qu, W., Wang, Y., Wan, H., and Tian, C. [Hypoglycemic effect of saponin from Tribulus terrestris]. Zhong.Yao Cai. 2002;25(6):420-422.
6. Gauthaman, K., Adaikan, P. G., and Prasad, R. N. Aphrodisiac properties of Tribulus Terrestris extract (Protodioscin) in normal and castrated rats. Life Sci 8-9-2002;71(12):1385-1396.
7. Bourke, C. A., Stevens, G. R., and Carrigan, M. J. Locomotor effects in sheep of alkaloids identified in Australian Tribulus terrestris. Aust.Vet.J 1992;69(7):163-165.
8. De Combarieu, E., Fuzzati, N., Lovati, M., and Mercalli, E. Furostanol saponins from Tribulus terrestris. Fitoterapia 2003;74(6):583-591.
9. Gauthaman K, Adaikan PG, Prasad RN. Aphrodisiac properties of Tribulus Terrestris extract (Protodioscin) in normal and castrated rats. Life Sci. 2002 Aug 9; 71(12): 1385-96.
10. Gauthaman K, Ganesan AP, Prasad RN. Sexual effects of puncturevine (Tribulus terrestris) extract (protodioscin): an evaluation using a rat model. J Altern Complement Med. 2003 Apr; 9 (2): 257-65.